Cairo: An Egyptian soldier was killed and four others were injured when a roadside bomb targeted an armoured military vehicle in restive Sinai Peninsula.
"The soldiers were immediately transferred to Arish military hospital, three of the four are in critical condition," Egyptian daily Youm 7 quoted medical sources.
The official security source said that efforts were intensified in the region to find and arrest the terrorists.
Sinai is facing a series of terror attacks since the ouster of ex-president Mohamed Morsi.
Security forces are struggling to quell an Islamist insurgency that has killed scores of soldiers and policemen in the peninsula bordering Israel and the Palestinian Gaza Strip.
Ansar Bait el-Maqdes, the dominant jihadist group in the Sinai, is only one to have claimed responsibility for more than one attack in the area since last year.